/* @(#)s_frexp.c 1.4 95/01/18 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunSoft, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice 

 * is preserved.

 * ====================================================

 */

/*

 * for non-zero x 

 *	x = frexp(arg,&exp);

 * return a double fp quantity x such that 0.5 <= |x| <1.0

 * and the corresponding binary exponent "exp". That is

 *	arg = x*2^exp.

 * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg 

 * with *exp=0. 

 */

#include "fdlibm.h"

#ifdef __STDC__

static const double

#else

static double

#endif

two54 =  1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */

#ifdef __STDC__

	double frexp(double x, int *eptr)

#else

	double frexp(x, eptr)

	double x; int *eptr;

#endif

{

	int  hx, ix, lx;

	hx = __HI(x);

	ix = 0x7fffffff&hx;

	lx = __LO(x);

	*eptr = 0;

	if(ix>=0x7ff00000||((ix|lx)==0)) return x;	/* 0,inf,nan */

	if (ix<0x00100000) {		/* subnormal */

	    x *= two54;

	    hx = __HI(x);

	    ix = hx&0x7fffffff;

	    *eptr = -54;

	}

	*eptr += (ix>>20)-1022;

	hx = (hx&0x800fffff)|0x3fe00000;

	__HI(x) = hx;

	return x;

}